The Mechanical Pencil seems obsolete, you can't change it's size. I can barely see it on my 4K monitor. And it's even hard to see in 1080p.

I think it can be replace with a more useful tool. Maybe something like a "Magic Color Eraser Tool"? It's better than be in "Custom" Air Brush. The "Magic Color Eraser Tool" can be added with more options, like to remove colors more accurately without erasing other colors from lines. Maybe add a range option? Also maybe you can add another another option, like erasing like 2 or 3 specifically colors with one tool with one stroke, while leaving the other colors 100% intake.